Frans,
I have used the Evans in a stock trigear and have found my CHTs were
about 15 degrees cooler with the glycol.
I am as perplexed as you why the difference in the coolant temp probe
performance.
I cannot imagine that the Evans would be too thick for the Laminova heat
exchanger as the coolant is basically the same viscosity of the Ethylene
glycol.
Are you using the S34 heat exchanger? That is what I thought about
testing.
Discussion:
I would expect you to see what I and others have seen with the Evans,
that is about a 15 degree CHT rise as the heat transfer rate of the
Evans is slightly less than the glycol. For a properly set up trigear
though, that would not be anything worth worrying about. The oil temp
should be nearly coolant temp once warmed up.
I hope not to insult you, but there are three or four types of Evans
coolants. Are you using the heavy duty (yellow NPG), high performance
(green which I used), NPG+, or Powersport which I think is NPGR. To my
knowledge, there is no viscosity difference with any of them and all
should work with the Rotax and Liminova.
I do know that the glycol cooler must be free of water or things to to
hell until the water evaporates. It was like oil and water but the
Rotax still cooled.
It almost sounds like the water pump inlet hose was kinked after the
flush and blocked the flow. Easy done.
Bud Yerly
Europa Tech Support.
----- Original Message -----
From: Frans Veldman<mailto:frans@privatepilots.nl>
To: europa-list@matronics.com<mailto:europa-list@matronics.com>
Sent: Saturday, February 25, 2012 11:45 AM
Subject: Europa-List: Laminova heat exchanger and Evans coolant
<frans@privatepilots.nl<mailto:frans@privatepilots.nl>>
Hi everyone,
As some of you know I have drastically changed the cooling system of
my
914 powererd Europa and achieved perfect cooling without having to
resort to more and larger openings in the cowling. Even better, I
think
I have only about 50% of the original air flow left at maximum cowl
flap
angle and about 10% of this during the cruise. Less cooling air is
less
cooling drag, which is a significant percentage of the total drag of
an
Europa. It is one of the keys why I can easily cruise at 140 knots
with
my hi-top tri-gear. (Sorry, still didn't got time to write the
promised
article about this).
So, with so much cooling overcapacity I thought to make the transition
from 50/50 to Evans coolant. Reason for that was to be able to allow
the
engine to run slightly hotter (good for the efficiency) and to have
zero
pressure in the cooling system (which is good in case of a leak).
One key element in my cooling system is the Laminova oil to water heat
exchanger. This marvel has very fine oil and coolant passages to
ensure
good heat transfer.
After swapping the 50/50 coolant for Evans I started the engine... and
it was interesting to see the CHT's to increase very fast to 100C
while
the coolant sensor was still at ambient temperature. Coolant flow in
the
system appeared to be about zero.
I thought of an air lock initially, but after much rocking and
disconnecting hoses at key locations I was quite sure that I didn't
have
an air lock (I never had to resort to any of such trickery during the
cooling experiments with 50/50).
So, that Evans stuff simply appears to be too thick for the tiny
canals
of the Laminova heat exchanger. When the oil finally warms up by
itself
(without the use of warm coolant as usually was the case, so this
takes
a long time) the flow improves somewhat, but the best I got was a 30C
difference between the CHT and coolant (on the ground at low power).
It
is not flyable. With 50/50 the temperature difference between the CHT
and coolant is almost nothing, indicative for sufficient coolant flow.
So, my question to anyone who has or is using Evans coolant: Did you
see
a large difference between the CHT's and coolant temperature? Has
anyone
ever tried to use Evans in combination with a Laminova/Mocal heat
exchanger?
On the Evans website a new type of coolant is announced, with higher
viscosity especially for motorcycles that have smaller radiators with
smaller canals. (Apparently there are more folks having problems with
the regular thick Evans stuff). Has anyone tried that in an Europa?
And
more importantly, am I allowed to use it in my Rotax?
I'm back to 50/50 for the moment (too bad for my dewatering efforts
prior to pouring in that Evans stuff).
Anyone interested in my can of Evans NPG+? Used only once! Never flown
with it.
Frans
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